Ultrasound is not always visible in the first month of pregnancy, ultrasound is recommended at six weeks of pregnancy is better.
If the menstrual cycle is regular and is within 30 days, the pregnancy sac can be seen after 35 days of pregnancy by ultrasound, if the menstrual cycle is greater than 30 days, the intrauterine gestational sac will need to be seen around 42 days of pregnancy, which will usually depend on when the fertilized egg is implanted.
One month after pregnancy, you can have blood drawn to check the level of human chorionic gonadotropin in the serum to confirm the pregnancy. One week later, you can have ultrasound, in which you can see the gestational sac in the uterine cavity to determine that it is an intrauterine pregnancy. Usually, ultrasound is done at 6 to 7 weeks to determine the fetal buds and the fetal heart, and you may not see any gestational structures when you have ultrasound done too early.
You should pay attention to rest, avoid overwork, take folic acid on time as prescribed by your doctor, and have your maternity checkups on time.